PROJECT ABSTRACT The general aim of this project is to exploit the international variation of health and life circumstances in Continental Europe to identify which interactions of bio-medical and socio-economic conditions over the life course affect cognition in later life. The project will leverage the EU-funding of the Survey of Health, Aging and Retirement in Europe (SHARE) and addresses a number of key research priorities for NIA: The study of older adults in a diverse array of countries will provide valuable information on cognitive status and relate it to the socio-economic and social environment of the elderly as well as biomarkers that may serve as instruments to target early prevention measures. It will enhance our understanding how the vastly differing social, health and long-term care systems affect mental health and resulting mortality of the aging populations. This holds especially for the life circumstances in Europe since World War II which are likely to have influenced cognitive decline now at older ages. Moreover, the large variation in key policy variables, e.g. retirement age, identifies pathways from early retirement through inactivity and loss of social contacts to lower cognition, mediated by education, working environment and other socio-economic factors over the life-course. SHARE is a large population-representative panel study closely modeled after the US Health and Retirement Study (HRS) in currently 27 Continental European countries plus Israel. Strictly harmonized health variables for the about 80,000 respondents include self-reported health, functional health, physical measurements such as grip strength, peak flow and chair stand, and a large battery of tests for cognition and mental health. Moreover, SHARE has collected dried blood spot samples from some 27,000 respondents. The project will fill two strategic gaps in the harmonization between HRS and SHARE. It will 1. Administer an in-depth measurement of cognition according to the Harmonized Cognitive Assessment Protocol (HCAP) that has been developed for the HRS-style aging surveys supported by NIA. 2. Analyze the blood collected by SHARE for blood lipids and other biomarkers that have been found to correlate with cognitive decline, vascular dementia and Alzheimer's disease. Using these data, the project will estimate prevalence rates of mild and severe cognitive impairment in the SHARE countries; compare these with HRS and other participants in the HCAP studies; and exploit the international variation of the SHARE plus SHARE-HCAP data in order to identify which interactions of biomedical and socioeconomic conditions over the life course affect cognition later in life. This project is synchronized with the long-run agenda of the SHARE panel which has collected blood in wave 6, is currently administering a life-history module in Wave 7 and will feature an extended cognition module in Wave 8. Funding is restricted to the additional data collection efforts for SHARE-HCAP and the analyses of blood taken in wave 6 and in the SHARE-HCAP substudy for markers associated with cognitive decline.